thanks for all of you guys here. trying to help will go and look at the local scrap yard. maybe I can find one
@gimpyshotrods , I’m not looking to pick a fight but how do you explain the ‘66 283’s for example. Was it just creative marketing when they offered the 283/195 horsepower with a Rochester 2 barrel and the 3733341 camshaft and also the 283/220 horse with the Rochester 4GC? Same heads, cam, compression ratio and distributor yet there was a 25 horsepower gain. Could they have seen the increase with dual exhaust if that was used on cars sold with the 220 HP engine?
The plenum and runners on that original 2-barrel manifold were smaller than on the 4GC manifold. That increased low-end torque, at the expense of peak horsepower. The torque curves of those two configurations indicate that the 2-barrel configuration was a better option for the street. Yes, improved exhaust would free up horsepower and torque, but that would necessitate ditching the factory exhaust manifolds for maximum effect. Now, those potentially increased peaks may not then fall where they are useful in a street car. Also, absolutely no performance numbers from GM, in that era, are to be considered valid. If, and it is a big IF they are close to correct, it is at the crank, with no accessories, including the water pump, in a laboratory, under ideal conditions, including active exhaust gas evacuation.
Thank you, I never considered the torque curves. Horsepower ratings raise eyebrows but it’s torque that gets you off the line.
Where are you located out of curiosity ? How much seriously do you think it was going to cost ? Manifolds are cheap - less than $200.00 https://www.summitracing.com/parts/edl-2701/make/chevrolet Carburetors have gone up - $429.00 https://www.summitracing.com/parts/edl-1406 Jegs will be the same way Want cheap(er) - go to a junk yard or swap meet. No matter what you pick, you'll need toRe-Kit the carburetor / new gaskets etc This isn't your first rodeo at ( per your Bio 72 years old) Where are you located ? 10 posts in 9 years ? Where you been ?
Not arguing theory, etc. In the late 80’s my then brother in law had a 77 or so Chevy PU. We found a used Performer and put it on with his quadrajet to replace the CI intake. He pulled a horse trailer with two in it near ever weekend to work at the same place. First trip back he called and said the “hill” that made the engine sluggish, didn’t have that anymore with the different intake. The only adjustment was to set the time to the spec under the hood, it wasn’t checked prior, but the timing had to be within 2 degrees of factory spec every two years to pass smog.The HEI couldn’t have been that far off
@gimpyshotrods I agree that street use should be optimized for low to mid RPM torque. However, I think that the 'more HP' thing is semantics. It's just like saying "it's not vacuum, it's low pressure". In the specific case being discussed, the 2bbl carb and intake on a SBC is a limiting design compared to a 4 bbl carb and intake. It may work okay in a low RPM, street application, but it is not as great a fuel/air mix unit compared to a Q-jet primary (completely ignoring the secondary side). I won't try to find HP/TQ dyno curves, since like you said, finding real reliable data is tough. I have heard many times that swapping helps with power and economy (not scientific, I know). The people that run limited class circle track have done wonders with 2bbls (High RPM), but the stock stuff was designed for a cost point and is not optimized.
Anytime you replace a malfunctioning part with a functioning part you improve performance pulled a faulty 4v and replaced with a good 2v and the truck ran much better. doesn’t make the 2v better for performance Just means I replaced a faulty part
You're getting some terrible responses. A 4 barrel will be a great upgrade. I would look for a OE, pre emissions, Q-jet intake and carb. Fakebook Marketplace or a swap meet is where I would look. Check the carb for fairly snug throttle shafts.
I know all the really fast guys running 10 seconds and under in the quarter mile are running stock 2 barrels.....
Looks like a lot of over engineering on this one. The only thing he said is make it run better. He didn’t say anything about it performing better. And based on his comments as far as the money tree with a four barrel intake and a four barrel carb, I would bet if he just took the two barrel off, cleaned it up put a brand new carb kit in it and 25.00 later it runs better.
@corncobcoupe I agree. I hope he's got a decent core. Those are mostly worn out by now. A quick look showed used rebuildable are 40-80 bucks reman are 450 (!) and kits and parts are here. https://www.carbjunkys.com/category-s/168.htm
Some of the offshore knock-offs are actually not bad. I have a customer who is running a really cheap 2-barrel, because he figured it was little to lose. It has been on the truck for about 2-years, with no issues.
Further explanation of "better" would be useful. If the original carb is full of varnish from sitting, or today's fuel, then a carburetor kit installed would probably make it run "better". Gimpy's comments about torque and power are spot on! For 1/4 mile at WOT, a 2-barrel that will flow enough air will probably (depending on intake manifold efficiency) SLIGHTLY outperform a 4-barrel; at the expense of driveability and fuel economy for street use. A reasonable sized 4-barrel (with an intake of equal efficiency) WILL improve street driveability as well as fuel economy over a 2-barrel with the same air flow (remember rated flows will differ because of the rating scale, by same air flow I mean exactly that, not a "rated" figure). What is a "reasonable size"? FACT! In 1957, when Mr. Duntov wanted a carburetor for the "race" edition of the 1957 Corvette 283, he chose a Carter WCFB 2493s. Carter 2493s was flowed by CARTER ENGINEERING, and rated by engineering, not marketing, at 380 CFM. As far as "reliable" published ratings, todays' ratings are probably somewhat more reliable than those from the 1960's; but I know of one major manufacturer of carburetors that did not have a 600 in their catalog, so marketing had production issue a new identification number for a 625 but it was marketed as a 600. Marketing is marketing! So what is "better"? Reliability, driveability, fuel economy, power, bragging rights??? With no additional information, a FLAPS kit just might be the answer. Jon
Concur on the FLAPS kit! Those "money trees" are almost as ellusive as the "fountain of youth". I have yet to find either of them ! Jon
In the spirit of a good discussion, really not looking to argue or get into a pissing contest, let's peel this back a bit. I posted earlier that I've had "seat of the pants" results showing a good improvement from replacing a stock 2 barrel intake with an aftermarket 4 barrel intake. I don't have dyno sheets to prove it, or timing slips, but I have the personal perception of an improvement. That's pretty anecdotal, I'll admit. However, go on to youtube and search out videos of dyno tests comparing the performance with carburetor and intake swaps, you'll find plenty. Obviously there is potential for improved performance from an intake swap, though admittedly it may involve a compromise on low speed torque, and/or throttle response. Or you could say that 1 intake limits power less than another, but that's just semantics, the point is that an intake system with more airflow and fuel capacity can result in improved performance vs one with more restricted airflow & fuel capacity, even with no other changes performed in the engine. BTW, just claiming your argument is right because of your credentials is a logical fallacy known as Appeal to Authority. An argument must be judged solely on it's content, not on the credentials of the person making it. Again, not picking a fight, just enjoy having a good discussion. I'm open to learning, and not interested in fighting with anyone. I'm done with that. Think of it as if we were together in person hanging around in the shop just bench racing.
That's the same question I have when I see online discussions about which carb is best and people argue that Holly's are better than Edelbrock and vice versa. People have strong opinions, but I never see an explanation of what is meant by "better".
For an excellent read I present the dual plane intake shootout with dyno proven results. The intakes varied 25 hp and 15 ft lbs torque https://www.hotrod.com/how-to/dual-plane-intake-manifold-comparisons/ And the same test with single plane intakes on the same engine https://www.hotrod.com/how-to/19-single-plane-small-block-chevy-intakes-test/ Certainly shows how an intake can effect hp an tq numbers !
Years ago I saw a 58-62 Corvette at my local drag strip (Dragway Park Cayuga). It was owned/raced by Stedelbauer Motors, a GM dealership. They ran it in Super Gas (9.90 class I believe), and it had a two-barrel on it. Admittedly, the reason I remember it IS because it was definitely the only car I spotted running a two-barrel carb. Looked outta place but man that thing ran great. I had a 72 Challenger (318) with a two-barrel and that thing ran fantastic with the factory two-barrel. Now that being said, regardless of how well a two-barrel can run, I am first in line to replace any cast iron intake and two-barrel carb with an aluminum intake and four-barrel. When I assembled the engine in my daily (350 SBC), I didn't go looking for a cast two-barrel intake and carb, I installed a Performer and Quadrajet. If scrounging the wreckers, keep an eye out for a factory aluminum intake on some 305's. Nothing wrong with tossing one of them on. As others have mentioned, if you post your location, maybe someone close has what you're looking for.
A change from 2 bbl to 4 bbl carb and manifold may or may not improve performance ( hp and torque) depending on the engines cam, heads exhaust etc. Air/fuel = power out. @Mummert had a great thread on carb selection a while back, excellent stuff! https://www.jalopyjournal.com/forum/threads/need-help-choosing-a-4-barrel-carburetor.1328048/ Dan
Ironman 3452 you might contact @carbking and get his input. He is very knowledgeable, and easy to talk with, tell him what you’re expecting to accomplish and he’ll set you on the proper course- I’m speaking from experience. Dan
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